Death Penalty for Not Praying?

Re: Death Penalty for Not Praying?

Religious matters are not personal if state and the people have the same religion that is Islam. That's where Amr bil maaroof wa nahi anil munkar really comes in...

So under amr bil maaroof, what exactly is involved? I can understand that not paying zakat is punishable, given the fact that you're able to pay in the first place. But what is the punishment? A fine? or Death?